Artificial hand



June 24, 1930.. D. w. DORRANCE 6 ARTIFICIAL HAND Filed Dec. 6, 1928 2 Sheets-Sheet 1 David W: Dorrance,

June 24, 1930- u. w. DORRANCE 8, 3

- ARTIFICIAL HAND Filed. Dec. 6, 1928 -2 Sheets-Sheet 2- Davol WDorranc'e,

Patented June 24, 1930 UNITED STATES oFricE,

DAVID W; DORR-ANCE, OF SAN JOSE, CALIFORNIA' ARTIFICIAL HAND 7 Application filed December 6, 1928. Serial No. 324,157.

The object of the invention is to provide an The fingers A and B are pivotally mountartificial hand consisting of dual compleed on a frame C of which the coupling D is mentary fingers and an actuating wedge by made a part and constitutes the means for rewhich the fingers are swung towards and leasably connecting the hand with an arm away from each other, but wherein the fingers stump member. The fingers are actuated to are pivotally mounted on a frame stationary open and close by means of a wedge member with'the arm carried member and the wedge 10 of the general shape of an arrowhead, said movable with respect to such frame; to prowedge member being slidably mounted onla vide a device of the nature above indicated guide post 11 upstanding from the base 12 of 10 in which the wedge is held yieldingly in rethe frame, the coupling memberD being made tracted position (or closed position for the a part of the frame by virtue of connection fingers) by a duality of resilient or elastic with said base member. In addition to the members of which one is mounted on each base, the frame O comprises spaced plates 14 side of the wedge; to provide an artificial secured to the base on opposite sides by 15 hand having complemental fingers ofwhich screws 15, one of the plates carrying posts 16 the terminals are disposed angularly to the constituting the pivotal mountings for the shank portions and at the same time angufingers A and B. The posts are secured to the larly with respect to the plane of movement plate by which they are carried preferably by of the fingers, so that a heavy object having a having reduced portions passed through the Z0 handle or other means which may be grasped plate and peaned over against the outer face between the fingers will not, in having its of the latter., The posts are detachably. conweight sustained, impose a strain on the finnected with the remaining plate, having regers in the direction of opening movement; duced portions entering eyes in the latter to provide a construction of artificial hand in and the posts being drilled and tapped for the which one of the fingers is provided with a reception of screws 17. This construction hook simulating the function of the thumb provides for the ready removal of one of, the on the human hand, said thumb hook being plates 14 after the removal of the post screws foldable down against the finger by which it is 17 and the corresponding base screws 15. carried when not in use; and to provide in a The base acts as a spacer between the plates device of the kind indicateda construction in at their lower ends and the posts as spacers which the number of operating parts are readjacent theupper end, the latter having the duced toa minimum and the'structure there additional function of pivotal supports for by so simplified as to besusceptible of cheap the fingers. V manufacture and low marketing cost. The wedge 10 moves up and down between 35 With this object in view, the invention conthe body portions 18 of the fingers and the sistsin a construction and combination of latter are provided with lateral extensible parts of which a preferred embodiment is feet 19 and 20, the feet 19 bearing upon oppoillustrated in the accompanying drawings, site sides of the .double inclined nose of the wherein: wedge andthe feet 20 011 the double inclined 40 Figure 1 is a side elevational view of a hand heel portion of the same. The inclined surconstructed in accordance with the invention. faces of the nose'portion are at a less acute Figure 2 is an edge elevational view. angle than the inclined surfaces, of the'heel Figure 3 is a top plan view. 7 portion and the feet 19 are farther from the Figures 4. and 5 are sectional views on the pivot points than the feet 20. "This arrange- 45 planes indicated by the lines 47-4: and '55, ment provides for ready opening of the finof Figure 2 respectively. gers by movement of the wedge but precludes Figure 6 is a sectional view'on the plane inmovement of the wedge by any forcetending dicated by the line 6-6 of Figure 1, the to open or spread the fingers, since in the folded position of thethumb hook being informer operation the sharp inclined surfaces dicated in dotted lines. of the nose may be readily employed to spread the fingers, while in the latter operation, where the fingers are presumed to be the operating means, they ing the wedge because of the slight inclination of the surfaces of the heel portion thereof. 7

The wedge is held normally ina retracted position at which time the fingers are in closed relation, the retracted position is yielding and consists of extensible members 21, preferably rubber bands, stretched over posts 22 and 23,

. 27 engaging the end the force arm of the lever having an eye 28 to which actuating means may be connected such for instance, as :a cord passed up the sleeve of the user and anchored at the shoulder in any acceptable manner. The appli- 7 wedge in opposition to the thus effecting opening .movement of I shank 29 is similar to the. shank 30 and hook 32.

on the lever actuating means The shank 30 V a slight curve and the shank 29 at its ]uncscribed, impose any 'A functioning merely cation of a pull on the cord as by the user extending the arm tensions the cord and thereby rocks the lever25 and extends the retracting means, the fingers,.their closing movement on the object to be grasped resulting when the pull is released because of the then following retraction of the wedge. v

The shanks 29 and 30 of the two fingers are formed integral with the bodyportions 18 thereof and the hooks'31 and 32 are angular integral extremities of the shanks, these hooks being at slight acute angles to the shanks and laterally deflected to be in a plane diagonal blends into the hook ture with its hook 31 is formed with a heel portion 33 the curve-between which and the the curve connecting Any object held between thefingers does not, by reason of the peculiar shape-just despread or open the fingers. If the object be held loosely as handle of a basket, its weight is sustained by the hook 32 andthat being disposed diagonally to the plane of the handle, imposed by the object carried by the former effects no strain tending to spreading movement of the fingers, the shank 29 of'the finger to prevent lateral displacement of the bail or handle on the hook are not effective in movbut the means for effecting said wedge, vanclng said wedge.

to the planes of the plates 1.4. 32 with.

lateral strain tending to e the bail of a bucket or the weight are complemental and when there is no ob- 1 ject to be held between the fingers and the latter used merely as grippers for the movement of objects, the two hooks then serve as a common hook, since they are held in close contactwith the wedge in its retracted position.

An auxiliary thumb hook 34: is provided on the finger A, this being 'pivotally mounted between ears 35 formed on the finger and secured by a pin 36 straddling said ears. In the extended position shown, the thumb hook may serve as a support for the handle of a knife; grasped'between the hooks 31 and 32 when the latter are merely functioning as clamping members,- as is when tools and the like are to be held. When not desired for use, the thumb hook may beswung over to the folded position indicated in dotted lines.

The invention having been described what is claimed as new and useful is:

1'. An artificial hand comprising a frame provided with means for connection to a stump carried member, complemental fingers pivotally mounted on the frame, a wedge member mounted for movement axially of the frame and having a double inclined nose portion and double inclined heel portion, said fingers having feet bearing on the inclined surfaces of the nose and heel respectively, resilient means normally retracting and mechanical means for ad- 2. An artificial hand comprising a frameprovided with means for connection to a stump carried member, complemental fingers pivotally mounted on the frame, a wedge member mounted for movementaxially of the frame, and'having a double inclined nose portion and double inclined heel. portion, sa1d fingers having p feet bearing'upon the 1nclmed surfaces of the nose and heel respect1vely, resilient means normally retracting frequently the case said wedgefand mechanical means for ad.-

vanclng said wedge, retracting meansc'on-' sisting of resilient membersdisposed on opposite sides of the frame andterminally se-,

cured to theeframe and wedge respectively. 3. An artificial hand comprising a frame consisting of a base member and plates secured to opposite sides of said base'member', posts spaced from the base member and complemental fingers spanning said plates, mounted for'rockmg movement on said posts, an actuatlng wedge slldably mounted'in the frame between said posts and having a 'double inclined nose portion "means for advancement of the wedge.

4. 'An artificial handcomprising afframe and double inclined heel portlon, the fingers having feet bearing on the V 125 inclined surfaces of the nose and heel por-- consisting of a base member, plates secured to opposite sides of the base'member, post-s spaced from the base member and spanning said plates, a guide post upstanding from the base member between and in parallelism with the plates, a wedge slidably mounted on said guide post between the first said posts, complemental fingers rockingly mounted on the first said posts, the wedge having a double inclined nose with a double inclined heel portion and the fingers having feet bearing upon the inclined surfaces of the nose and heel portions of the wedge, yielding means normally retracting the Wedge and mechanical means for advancing the wedge.

5. An artificial hand comprising a frame consisting of a base member, plates secured to opposite sides of the base member, posts spaced from the base member and spanning said plates, a guide post upstanding from the base member between and in parallelism with the plates, a wedge slidably mounted on said guide post between the first said posts, complemental fingers rockingly mounted upon the first said posts, the wedge having a double inclined nose with a double inclined heel portion and the fingers having feet bearing upon the inclined surfaces of the nose and heel portions of the wedge, yielding means normally retracting the wedge and mechanical means for advancing the wedge, and a lever rockingly mounted between the plates of the frame with one terminal exterior to the frame and the other in frictional contact with the end of the heel portion of the wedge.

In testimony whereof he affixes his signature.

DAVID W. DORRANCE. 

